Localización y valoración de fuentes de distorsión armónica y/o desequilibrio en redes eléctricas

En la actualidad, los consumos de potencia eléctrica se caracterizan por una amplia variedad de cargas en sus procesos productivos, en muchos de los casos cargas trifásicas/monofásicas constituidas por convertidores electrónicos de potencia. Por otro lado, los sistemas eléctricos están hoy día evolucionando hacia sistemas de generación descentralizados donde las unidades de generación, principalmente de energía renovable, se conectan mediante convertidores electrónicos directamente a las redes de distribución. Los consumos referidos y la generación distribuida, contribuye al crecimiento de las corrientes armónicas y desequilibradas que conllevan, entre otros, a un aumento de las pérdidas de la red, y mal funcionamiento de los equipos. Desafortunadamente, la identificación de estas fuentes de perturbación no puede lograrse por medio de medidas individuales en una sección determinada de un sistema eléctrico. La solución efectiva del problema requiere tener que conocer las medidas simultáneas de los parámetros eléctricos de calidad de todas las acometidas donde estén conectados los consumidores. En efecto, los índices empleados usualmente para valorar la calidad, principalmente la tasa de distorsión armónica, no son apropiados para evaluar la calidad de la energía eléctrica cuando está presente una fuerte distorsión, y especialmente en aquellos casos donde existen múltiples fuentes de perturbación conectadas a la red. Por otra parte, se ha demostrado que las medidas de la calidad de la energía eléctrica llevadas a cabo en una sección de medida determinada de la red, no pueden suministrar la información suficiente al menos sin recurrir a mecanismos de medida invasivos. Así, en la bibliografía se encuentran diferentes enfoques para abordar este tipo de cuestión. Estos pueden clasificarse en dos grupos: métodos de medidas en una sección localizada, y métodos de medida distribuidos multipunto (medidas efectuadas simultáneamente en diferentes secciones de la red). Los métodos basados en medidas realizadas en un punto de la red tienen como ventajas principales su bajo coste y su fácil implementación en las instalaciones, pero en algunas condiciones pueden registrar una información inexacta respecto del estado de perturbación de la red. Por otra parte, los métodos de medidas distribuidas multipunto registran una información más precisa respecto del estado de distorsión y desequilibrio del sistema de potencia completo, aunque en la práctica hasta ahora sean difíciles de realizar y requiera una instrumentación más compleja tanto desde el punto de vista de hardware como de software. Además, este enfoque exige la definición de nuevos índices y los correspondientes métodos de medidas asociados para la evaluación de los niveles de las perturbaciones periódicas en la sección de medida. Este enfoque es el que se considera que puede resolver de forma definitiva la cuestión y el que se plantea en esta tesis. En esta tesis se propone un nuevo índice basado en medidas distribuidas multipunto para la identificación de distorsión armónica y/o desequilibrio. El índice propuesto está construido a partir de términos de potencia dentro del marco del estándar IEEE 1459. El estándar presenta un modelo de descomposición de la potencia aparente en condiciones de distorsión y asimetría, sin embargo, éste carece de una evaluación práctica del desequilibrio causado por la carga. El algoritmo propuesto se define usando un nuevo método de descomposición de potencia aparente que lo separa en cuatro componentes, así el nuevo índice introduce dos novedades significativas. En primer lugar, se define en función de términos de potencia desarrollados según la misma filosofía de trabajo que el estándar IEEE 1459. Y en segundo lugar, los términos de potencias utilizados representan una evolución de los términos del estándar, ya que separan de forma más completa la distorsión y el desequilibrio. La nueva propuesta de índice se valida a partir de dos plataformas: una de simulación en el entorno de MATLAB/Simulink y otra experimental desarrollada en el laboratorio de potencia del grupo de investigación. La tesis se ha organizado de la siguiente manera: en el capítulo I se estudia el problema de la distorsión armónica y el desequilibrio en los sistemas eléctricos de potencia de forma conceptual, además se plantea una clasificación de los métodos de localización de fuentes de perturbación. En el capítulo II se realiza un estudio de los métodos basados en medidas realizadas en un único punto de la red. El capítulo III tiene un doble objetivo, por un lado se presentan los índices distribuidos multipunto más representativos recogidos en la literatura técnica, y por otro, se desarrolla la nueva propuesta de índice de medidas distribuidas para la identificación de fuente de distorsión armónica y/o desequilibrio en la red, basado en términos de potencia en el marco del estándar IEEE 1459. En el capítulo IV, con el objetivo de contrastar y validar la nueva propuesta, se realiza un análisis comparativo de los índices distribuidos multipunto a través de una plataforma experimental. Por último, en el capítulo V se presentan las conclusiones de este trabajo.At present, electric power distribution is characterized by a wide variety of loads at its points of production, with, in most cases, electronic power converters comprising singlephase or three-phase loads. As power networks develop towards decentralized generation systems, more units, largely from renewable sources, are being directly connected to the distribution network through electronic converters. Irregular patterns of consumption alongside this distributed generation, contribute to an increase in harmonic distortion and current unbalance that together lead to an increase in network failure and equipment malfunction. At the same time, the very elements that have allowed the development and modernization of electric power distribution networks are those that display greater sensitivity to the disturbances (that they cause) in the network, endangering the system. Consequently, identification of harmonic distortion and/or unbalanced sources in the system is essential, both to demand responsibility from the originator/s (the electrical supply system and/or customer installation), and to take the necessary measures to solve the problem. The different approaches to tackling this problem can be classified into two groups. The first approach concerns measurements taken from a localized section (single-point), while the second concerns multi-point distributed measurement methods (that is, measurements taken simultaneously at different sections on the distribution network). Single-point measurements offer the advantages of low cost and ease of implementation, but in some conditions the information recorded with regard to the state of network disturbances can be inaccurate. The multi-point methods enables the recording of accurate information regarding the state of distortion and unbalance of the complete power system, and is consequently considered capable of definitively resolving the issue. In practice, however, approaches of this nature have to date proved difficult to perform and require the use of expensive and more complex instrumentation from both a hardware and software perspective. What is required is the definition of new indices and corresponding methods for evaluating of the levels of periodic disturbances in the measurement section. Currently, advances in digital signal processing techniques and the interconnection of equipment allowing real-time communication over communication networks make it feasible to address the practical development of a distributed measurement system aimed at quality power in electrical networks. However, it is necessary to define a distributed index that computes the information received from the different locations. These indices are formed from the combination of three indices that have been extensively used to assess distortion and unbalance by single-point methods. The combination of these presupposes greater success in the identification of periodic disturbances. Tests in different conditions have demonstrated that they cannot always clearly identify the source of disturbance, for which reason new proposals would be welcome. This thesis proposes a new multi-point distributed measurement index for the identification of the sources of harmonic distortion and/or unbalance, based in power terms on the IEEE Std. 1459 framework. The Std. 1459 presents a model of apparent power decomposition terms in conditions of distortion and asymmetry. However, this model lacks a practical assessment of the unbalance caused by the load. The new index algorithm is defined using a new method of apparent power decomposition which separates it into four components. The new index introduces two significant developments. First, it is defined as a function of power terms in the Std. 1459 framework, although it retains a fourth perturbation term. And second, the power terms used represent an evolution of the Std terms that most clearly separate distortion and unbalance. The index is applied and validated by means of an experimental platform connected to a real, low-voltage network. The thesis is organized as follows: in chapter I we study the problem of harmonic distortion and imbalance in electrical power systems in a conceptual way, in addition to a classification of the methods of locating sources of disturbance. In Chapter II a study of the methods based on measurements carried out at a single point in the network is carried out. Chapter III has a double objective, on the one hand the most representative multipoint distributed indices of the technical literature are presented, and on the other, the new proposal for the index of distributed measures for the identification of harmonic distortion source and/or unbalance is presented in the network, based on terms of power within the framework of the IEEE 1459 standard. In Chapter IV, in order to contrast and validate the new proposal, a comparative analysis of the multipoint distributed indices is carried out through an experimental platform . Finally, chapter V develops the conclusions

Neuronal nuclear tau and neurodegeneration

Tau is a well-known microtubule-associated protein related to its cytoplasmic localization in a neuronal cell. However, tau has been located at the cell nucleus where it could be a nucleic acid-associated protein by its preferential binding to DNA sequences present in the nucleolus and pericentromeric heterochromatin. This less well-known localization of tau could not be trivial, since during aging, an increase in the amount of nuclear tau takes place and it may be related to the described role of tau in the activation of transposons and further aging accelerationWork in the laboratory of JA is funded by grants from the Spanish Ministry of Economy and Competitiveness (PGC-2018-09177-B-100). Work in the laboratory of FH is funded by grants from the Spanish Ministry of Economy and Competitiveness (Ministerio de Economía, Industria y Competitividad, Gobierno de España, PID2020-113204GB-I00) and was co-financed from the Comunidad de Madrid through Structural Funds of the European Union [S2017/BMD-3700 (NEUROMETAB-CM)

Control strategy for hybrid power filter to compensate unbalanced and non-linear, three-phase loads

A control algorithm is proposed for a three-phase hybrid power filter constituted by a series active filter and a shunt passive filter. The control strategy is based on the dual formulation of the vectorial theory of electrical power, so that the voltage waveform injected by the active filter is able to compensate the reactive power, to eliminate harmonics of the load current and to balance asymmetrical loads. An experimental prototype was developed and experimental results presented

Distortion Sources Identification in Electric Power Systems

.Distorted voltage and current waveforms is one of the problems associated to electric power quality. Continuous use of non-linear loads provokes the existence of voltage waveforms with a high distortion. Thus, it is necessary to know the responsible of this problem by means of the commonly named distortion sources identification. In this paper, the problem is analyzed through the harmonic power sign, with the objective of knowing the sense of harmonic power flow between source and one load in distorted systems. Nowadays, it has already been established in the Literature that an analysis of this kind does not solve the problem. Recently, new indices have been introduced to evaluate a specific consumer distortion level. In this paper, a comparative analysis of these indices is carried out, having as reference a practical case. The results obtained show that, in fact, these indices can help to valuate the harmonic distortion, although none of them solve the question definitively

Agenesia de arteria pulmonar derecha en un neonato. La excepcionalidad del diagnóstico en período perinatal

Pulmonary artery agenesis is a congenital disorder that is usually linked to other congenital cardiac diseases, being infrequently found on an isolated manner. Although it can cause symptoms during childhood, pulmonary arteries isolated anomalies are frequently unnoticed until adolescence or early adulthood and for this reason, its perinatal diagnosis is quite unusual. A case of a newborn is presented in whom a computed tomography angiography (CTA) is performed to confirm the diagnosis of right pulmonary artery agenesis.La agenesia de arteria pulmonar es un trastorno congénito que normalmente se encuentra asociado a otros defectos cardiacos congénitos, siendo extraño que se presente de manera aislada. Aunque puede causar síntomas durante la infancia, las anomalías aisladas de las arterias pulmonares pasan con mucha frecuencia inadvertidas hasta la adolescencia o la edad adulta temprana y, por eso, su diagnóstico en período perinatal es muy poco frecuente. Se presenta el caso de un neonato al cual se le realiza una angiotomografía computarizada (angio TC) para la confirmación del diagnóstico de agenesia de la arteria pulmonar derecha

Distortion and Unbalance Assessing Indices Using Commercial Analysers

Power quality monitoring is assuming an increasing importance because of the large diffusion of nonlinear and time - varying single - phase and three - phase loads and t heir interactions with the power supply system. This has made that the industrial electrical consumer systematically uses measure equipment to evaluate the electric power quality. The measurements show that the harmonics of the waveforms are variable along with the time due to the changes in the load conditions and in the system configuration. Thus, the electrical users dispose of a great quantity of data from such of the three phases of the supply. Therefore, it is necessary to find a way to characterize t his great group of registered data. Thus, the objectives of this work are: firstly, to propose two indices, a three - phase total demand distortion index and a three - phase total unbalance index; secondly, this paper proposes a simple way to characterize the groups of data in an statistical way which make easy its representation. The study carried out is applied to the data recently registered in an electrical power system

Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis

[EN] An in-body sensor network is that in which at least one of the sensors is located inside the human body. Such wireless in-body sensors are used mainly in medical applications, collecting and monitoring important parameters for health and disease treatment. IEEE Standard 802.15.6-2012 for wireless body area networks (WBANs) considers in-body communications in the Medical Implant Communications Service (MICS) band. Nevertheless, high-data-rate communications are not feasible at the MICS band because of its narrow occupied bandwidth. In this framework, ultrawideband (UWB) systems have emerged as a potential solution for in-body highdata-rate communications because of their miniaturization capabilities and low power consumption.This work was supported by the Programa de Ayudas de Investigación y Desarrollo (PAID-01-16) at the Universitat Politècnica de València, Spain; by the Ministerio de Economía y Competitividad, Spain (TEC2014-60258-C2-1-R); and by the European FEDER funds. It was also funded by the European Union’s H2020:MSCA:ITN program for the Wireless In-Body Environ-ment Communication–WiBEC project under grant 675353.Garcia-Pardo, C.; Andreu-Estellés, C.; Fornés Leal, A.; Castelló-Palacios, S.; Pérez-Simbor, S.; Barbi, M.; Vallés Lluch, A.... (2018). Ultrawideband Technology for Medical In-Body Sensor Networks: An Overview of the Human Body as a Propagation Medium, Phantoms, and Approaches for Propagation Analysis. IEEE Antennas and Propagation Magazine. 60(3):19-33. https://doi.org/10.1109/MAP.2018.2818458S193360

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

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Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

Abstract Background Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres. Methods This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low–middle-income countries. Results In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of ‘single-use’ consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low–middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia. Conclusion This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high– and low–middle–income countries